Hand-held tube bender and bend centering procedure



JOHN H. STANLEY AVZM QZ J J. H STANLEY Filed Oct. 24. E 1965 HAND-HELD TUBE BENDER AND BEND CENTERING PROCEDURE United States Patent 3,416,345 HAND-HELD TUBE BENDER AND BEND 'CENTERIN G PROCEDURE John H. Stanley, Euclid, Ohio, assignor to Parker- Hannifin Corporation, Cleveland, Ohio, a corporation of Ohio Filed Oct. 24, B65, Ser. No. 504,951 4 Claims. (Cl. 72-159) ABSTRACT OF THE DISCLOSURE There are disclosed a method of and apparatus for setting up a tube bending operation employing a peripherally grooved radius block having a rabbeted edge presenting an outwardly facing peripheral shoulder and a planar ledge paralleling the center of the bending plane, means to secure a tube-to-be-bent, and a follower die grooved to partially embrace the tube and swingable about the block during a bending operation, the method comprising, marking the tube-to-be-bent at a point intended to lie centrally of the bend when completed, placing the tube with its center line in tangential relation to said shoulder, selecting a templet having converging edges defining therebetween an included angle corresponding to the angle of bend to be made in the tube, supporting the templet against the planar ledge with one of its converging edges against the outwardly facing peripheral shoulder and its other converging edge aligned over the tube center, sliding the tube along its center through the securing means and block groove to place the mark on the tube at the point of convergence of said templet edges, fixing the securing means on the thus placed tube and then proceeding with the bending of the fixed tube through the predetermined angle, thus to center the bend on the tube mark.

The invention relates generally to tube bending and seeks to provide a novel form of tube bender which is very simple in construction and subject to relatively inexpensive manufacture and wherein means and novel procedure are provided for centering bends of predetermined angles.

Hand-held and -operated tube benders have been known heretofore and have included grooved radius blocks, tube securing devices and bending dies or followers swingable about the radius blocks in the bending of tubes. Such benders have been in extensive use but have been relatively cumbersome, have had a tendency in some instances to partially flatten tubes during bending, and have been devoid of any simple and effective means and procedure for centering bends of predetermined and selected angles. It is a purpose of the present invention to provide a simple hand held and operated tube bender wherein tube bends can be formed without objectionable flattening of tubes during bending, and which are capable of centering the bends as desired, a simple procedure for employing the novel bender in the formation of centered bends also being comprehended.

In its more detailed nature the invention resides in providing a tube bender of the character stated including a peripherally grooved radius block the groove in which is deepened by two outwardly extended parallel wall portions, means for securing a tube to be bent to the block, link and tube bending follower means swingable about the block, and handle means manually operable and projecting from the block and link means respectively, the radius block having an in-part circular periphery an edge of which is rabbeted to present an outwardly facing in-part circular shoulder disposed to directly overlie the center of a tube in place in the block groove prior to and during Patented Dec. 17, 1968 bending to serve as an accurate sighting line indicating the positioning of the tube center line, and also a planar ledge paralleling the tube bending plane and whereon to support a templet equipped with angularly related edges converging to define an included angle conforming to the degree of bend to be made in the tube, the point of convergence of the templet edges being placeable relative to a mark on the tube to determine the proper placement of the tube in the securing member and the radius block groove preparatory to the start of a bending operation.

Another object of the invention is to provide a tube bender of the character stated wherein the follower means comprises an elongated grooved die the groove in which is defined in part by a straight edge, the die and link also including stop means cooperatively engageable to place the die groove and straight edge in approximate tangential alignment with the radius block shoulder to aid in the sighting and template placement incidental to an initial mounting of a tube for bending.

The invention also comprehends a novel method of setting up a tube bending operation employing a tube bender of the character stated, said method comprising, marking the tube to he bent at a point intended to lie centrally of the bend when completed, placing the tube with its center line in tangential relation to the radius block shoulder, selecting a templet having converging edges defining therebetween an included angle corresponding to the angle of bend to be made in the tube, supporting the templet against the planar ledge on the radius block with one of its converging edges against the outwardly facing block shoulder and its other converging edge aligned over the tube center, sliding the tube along its center through the securing means and block groove to place the mark on the tube at the point of convergence of said edges, fixing the securing means on the thus placed tube and then proceeding with the bending of the fixed tube through the predetermined angle, thus to center the bend on the tube mark.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawing.

In the drawing:

FIGURE 1 is a plan view illustrating the improved tube bender with the bending tool set up for a bend.

FIGURE 2 is a plan view showing the tool of FIGURE 1 after completion of the 90 bend.

FIGURE 3 is a vertical cross section taken on the line 3-3 on FIGURE 2.

FIGURE 4 is a fragmentary side elevation showing the tube in place in the securing means and the groove of the radius block.

FIGURE 5 is 'an enlarged fragmentary sectional view illustrating the tube in the radius block groove which has been deepened by outward extension of opposing parallel walls, the provision of a templet receiving and supporting rabbet also being shown.

FIGURE 6 is a fragmentary plan view illustrating a chart which may be used and which has illustrated thereon a selected tube bend with the point of bend illustrated at the center of the intended bend.

FIGURE 7 is a somewhat schematic fragmentary view illustrating the manner of marking the tube preparatory to a bending operation and the setting up of the tool preparatory to the making of a 90 bend.

FIGURE 8 is a view similar to FIGURE 7 illustrating a tool set up for the making of a 45 bend.

In the example of embodiment of the invention herein disclosed, there is included a radius block or bend defining die 5 having a peripheral portion 6 extending about somewhat more than 180, and a flattened or chordal portion 7. The radius block includes a centrally raised portion 8 in which a handle 9 is secured in any approved manner to project radially as illustrated in FIGURES 1 and 2.

The radius block is centrally drilled at 10 to receive a shouldered pivot pin 11 whereon an inner end portion 12 of a link 13 is swingably mounted, as at 14. At its other or outer end 15 the link is bored with an elongated hole at 16 to receive a shouldered pivot pin 17 which is secured at 18 in a hole provided in the tube bending means, here in the form of a follower die 19. The follower die 19 has a straight edge face 20 which is placeable in relation to the periphery 6 of the radius block 5, as in FIGURE 1, the link 13 having a shoulder 21 which is engageable by a pin 22 depending from the follower to fix the stated relation of the follower die with the radius block in a tube bending set up, as illustrated in FIGURES l and 2.

A handle 23 is secured in any approved manner to the follower die 19 to project therefrom in cooperative relation with the radius block handle 9, and said follower die or shoe is equipped with a groove 24 positioned in its face 20 and shaped to substantially conform to the curvature of a tube T when presented in position for bending, as clearly illustrated in FIGURES l, 2 and 3 of the drawmgs.

It will be apparent by reference to FIGURES 1 to 3 that the follower die or shoe groove 24 opposes the tube receiving groove 25 formed in the periphery 6 of the radius block 5, said groove being shaped to conform to and receive a full half cross-section of a tube T. This groove is deepened by provision of two parallel opposing and outwardly extending fiat wall portions 26 which are effective, during tube bending, to overcome any tendency of the tube to flatten during the bending operation.

One corner or edge of the radius block periphery is rabbeted at 27 to provide upstanding, outwardly facing shoulder or wall 28 disposed, as clearly illustrated in FIGURES 1 through 5, to overlie the center line of a tube T positioned in the radius block groove 25 prior to and during bending operations. It will be apparent also from the illustrations referred to that the radius block edge rabbeting 27 provides a fiat planar ledge 29 paralleling the tube bending plane.

Securing means are provided for placing and holding a tube T in proper position in the groove 25 of the radius block 5. In this disclosure, the tube securing means takes the form of a clamp hook or securing clip 30- which is pivotally secured at 31 to the chordal face 7 of the radius block and is swingable to present its tube embracing seat 32 in position for receiving the tube T as illustrated in FIGURES 1, 2 and 4.

It will be apparent by reference to FIGURE 1 that the straight edge face portion 20 is so related to the shoulder and pin means 22, 21 that in the position of the parts shown in FIGURE 1 a template aligning abutment portion of the face portion 20 is placed to directly overlie the centerline of a tube mounted for bending and may be engaged by one of the converging edges of the templet as the other such edge 35 of the templet is engaging the radius block shoulder 28, thereby to aid in the sighting and templet placement incidental to an initial mounting of a tube for bending.

In the operation of the herein disclosed hand held tube bender, means and procedure are provided for accurately centering the bend. In accomplishing this purpose, a mark P preferably is placed on the tube T at a point which is to be centered on the bend in the tube when the same is completed by manipulation of the bender. In accomplishing this purpose, a chart, a fragment of which has been illustrated in FIGURE 6, may be used, said chart indicating by the mark P at the intersection of the converging lines the distance from the end of the tube at which the bend is to be made, this distance being schematically indicated at A.

After thus marking the tube, by inclusion of a chart reference, or without the benefit of the same, the marked tube is placed in the securing hook seat 32, as shown in FIGURES 1 and 4, and extending in straight line, as indicated in FIGURE 1, through the radius block groove 25, the follower means or die 19 preferably being swung away to its inoperative position. It will be recognized in FIGURE 1 that in this initial placement of the tube, the center line of the tube bears tangential relation to, and is directly centered beneath and in registry with, the outwardly facing wall 28 of the radius block rabbet 27.

Assuming that a bend is in contemplation, a 90 templet such as is illustrated at 33 in FIGURES 1 and 7 will be applied. It is to be understood that templets may be selected according to the angle to be bent in particular tubes, for example, a 90 templet 33 being shown in FIGURES 1 and 7, and a 45 templet 34 being shown in FIGURE 8. Each templet has converging edges 35 converging at a point 36 and defining between them the particular included angle corresponding to the desired bend in a particular tube.

When a chart is used to guide the marking of the tube at P, a chart such as indicated at 37 is employed whereon the tube bend selections may be depicted at 38, the converging center lines 39 indicating the point P at which the center of the bend is to be placed, said point P being designated at the indicated distance A from the tube end previously referred to.

In the set up for making of a 90 bend as in FIGURE 1, the converging edge 35 of the templet 33 shown horizontally in that figure is placed against the rabbet wall 28 and ersting on the rabbet ledge 29, and the other converging edge 35 of the templet is laid directly over the center of the tube T, as illustrated in FIGURES l and 7. With the templet thus placed, the tube T being secured in the seat 32 of the securing means and lying tangentially in the radius block groove 25, the follower or bend ing die 19 will be swung into the position illustrated in FIGURE 1 and then manipulated to follow about the periphery of the radius block 5 from the position illus trated in FIGURE 1 to the completion of the bend as illustrated in FIGURE 2, the bend, by this procedure, being perfectly centered on the tube mark P which had been placed by longitudinal sliding of the tube to cause the tube mark P and the converging point 36 on the templet to coincide.

When other angles of bend are to be made, see for example, the 45 bend indicated in FIGURE 8, by following the same practice of placing one converging templet edge 35 on the radius block ledge 29 and against the shoulder or wall 28, and the other converging edge 35 centrally over and along the center of the tube T, the templet point 36 or position of convergence of the templet edges 3535 will be properly positioned to determine the point at which the bend mark P on the tube should be placed, as previously described.

While specific part structures and arrangements have been illustrated by example herein, it is to be understood that variations may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. In a hand tool for bending tubes, the combination of a templet equipped with angularly related edges converging to define an included angle conforming to the degree of bend to be made in a tube, a radius block having an in-part circular periphery and a chordal face portion, said periphery having a groove therein shaped to receive a full half cross section of a tube-to-be-bent and to include two opposed parallel wall portions deepening the groove by extending tangentially outward away from the half-circular sectioned tube contacting portion of the groove and effective to overcome any tendency on the part of a tube being bent to flatten during bending, a handle rigidly secured to and projecting from the radius block, a securing member attached to said chordal face and engageable over a tube-to-be-bent to hold it in the radius block groove during a bending operation, a link pivotally connected with the radius block at the center of its in-part circular periphery to be swingable thereabout, tube bending follower means carried by the link and grooved to engage snugly about a substantial portion of a tube being bent as the link and follower means are swung about said radius block center, and handle means associated with said link and follower means for swinging them about the radius block during a bending operation, said radius block in-part circular periphery having a rabbeted edge presenting an outwardly facing in-part circular shoulder disposed to directly overlie the center of a tube in place in said peripheral groove prior to and during tube bending to serve as an accurate sighting line indicating the position of the tube center line, said rabbeted edge also presenting a planar ledge paralleling the plane of tube bending and whereon to support said templet the point of convergence of the templet edges being placeable relative to a mark on the tube with one said converging edge resting on said rabbeted edge and against said shoulder and the other of said converging edges overlying the center line of the tube being placed for bending to determine the proper placement of the tube in the securing member and the radius block groove preparatory to the start of a bending operation.

2. A hand tool for bending tubes as defined in claim 1 wherein the securing member is in the form of a hook flatwise opposed to and swingably attached to the chordal face of the radius block and having a tube embracing seat so formed and placed relative to the radius block groove as to be cooperable therewith and the outwardly facing rabbet shoulder in initially placing a tube for bending with its center in a straight line bearing tangential alignment with said shoulder along the portion of the tube to be bent.

3. A hand tool for bending tubes as defined in claim 2 wherein the tube bending follower means comprises an elongated grooved die wherein the groove is defined in part by a straight edge presenting a portion thereof as a templet aligning abutment, the die and link also including stop means cooperably engageable to place the die groove and straight edge in approximate tangential alignment with the radius block shoulder with said aligning abutment directly overlying the centerline of a tube mounted for bending, thereby to aid in the sighting and templet placement incidental to an initial mounting of a tube for bending.

4. The herein described method of setting up a tube bending operation employing a tube bender including a peripherally grooved radius block having a rabbeted edge presenting an outwardly facing peripheral shoulder and a planar ledge paralleling the center of the bending plane, means to secure a tube-to-be-bent, and a follower die grooved to partially embrace the tube and swingable about the block during a bending operation, said method comprising, marking the tube-to-be-bent at a point intended to lie centrally of the bend when completed, placing the tube with its center line in tangential relation to said shoulder, selecting a templet having converging edges defining therebetween an included angle corresponding to the angle of bend to be made in the tube, supporting the templet against the planar ledge with one of its converging edges against the outwardly facing peripheral shoulder and its other converging edge aligned over the tube center, sliding the tube along its center through the securing means and block groove to place the mark on the tube at the point of convergence of said edges, fixing the securing means on the thus placed tube and then proceeding with the bending of the fixed tube through the predetermined angle, thus to center the bend on the tube mark.

References Cited UNITED STATES PATENTS CHARLES W. LANHAM, Primary Examiner. R. D. GREFE, Assistant Examiner.

US. Cl. X.R. 72-459 

